Processing methods and processing apparatus

Abstract

A method and apparatus for processing a material are provided, the material being the upper layer from a metal melting process, the material containing one or more salts, the material containing one or more metals, the salts and/or metals being recycled as a result of the method/apparatus. The method includes feeding the material to a leaching step; obtaining a leachate from the leaching step; feeding the leachate to a drying step or spray drying step; obtaining a solid from the drying step or spray drying step. Off gases from the leaching step are used to provide heat to the drying step. The drying step provides a product well suited to being turned into pellets for reuse.

The invention claimed is: 
     
       1. A method of processing a material, the material being the upper layer from a metal melting process, the material containing one or more salts, the material containing one or more metals, the method including:
 a) feeding the material to a slag press and compressing the material; 
 b) feeding the compressed material to a size reduction; 
 wherein steps a) and b) are provided before the temperature of the compressed material has reduced below 350° C.; 
 the method further including: 
 c) reducing one or more dimensions of the compressed material in the size reduction step, the size reduction step including a crushing step; 
 d) feeding the crushed material to a leaching step; 
 e) obtaining a leachate from the leaching step; 
 f) feeding the leachate to a spray drying step; and 
 g) obtaining a solid from the spray drying step. 
 
     
     
       2. A method according to  claim 1  in which the leaching step further provides one or more other outlet streams, including an off gas stream, the off gas stream being further processed by combustion, with heat and/or power generated by the combustion being used in the spray drying step. 
     
     
       3. A method according to  claim 1  further comprising a step for feeding hot gas to the spray drying step, the hot gases being from an off gas stream processing and/or possessing energy generated by an off gas stream processing. 
     
     
       4. A method according to  claim 1  including the further step of compressing and/or moulding the solid into pellets. 
     
     
       5. A method according to  claim 1  wherein the leaching step comprises a multiple pass leaching process where multiple passes through one leaching tank are provided and/or a multiple stage leaching process where passage through a number of leaching tanks is provided. 
     
     
       6. A method according to  claim 1  including a step for obtaining a solid from the spray drying step, by separating the solid and a gas in the spray drying step. 
     
     
       7. A method according to  claim 6  including a step for compressing and/or moulding the solid into pellets in one or more further steps. 
     
     
       8. A method according to  claim 7  wherein the step for compressing and/or moulding is provided without adding any further components to the solid. 
     
     
       9. A method according to  claim 7  wherein the compressed and/or moulded solids are be fed to a furnace to provide a material on the surface of a molten metal in a furnace. 
     
     
       10. A method according to  claim 7  wherein the compressed and/or moulded solids are produced with a controlled ratio of sodium chloride to potassium chloride. 
     
     
       11. A method according to  claim 7  wherein the step for compressing and/or moulding solids is provided without adding any binders or moisture. 
     
     
       12. A method according to  claim 1 , wherein the one or more salts are selected from sodium chloride, sodium chlorate, potassium chloride, or potassium chlorate. 
     
     
       13. A method according to  claim 1  further comprising a step for the recycling of one or more metals produced. 
     
     
       14. A method according to  claim 1 , wherein steps a) and b) are provided before the temperature of the compressed material has reduced below 525° C. 
     
     
       15. A method according to  claim 1  further comprising a step for recycling one or more salts produced. 
     
     
       16. A method according to  claim 1  wherein the one or more metals are selected from aluminium or aluminium oxide. 
     
     
       17. A method according to  claim 1  wherein steps a) and b) are provided before the temperature of the compressed material has reduced below 760° C.